1. Field of Invention
The present invention relates to a method and an apparatus for cutting a strand of a slide-cut system used in a plastics pellet manufacturing apparatus.
2. Related art
An example of a conventional strand cutting apparatus used in a pellet manufacturing apparatus will be explained.
FIG. 13 is an explanatory schematic diagram showing the entire configuration of an example of conventional pellet manufacturing apparatuses of a strand-cut system. This pellet manufacturing apparatus is arranged in a manner that plastics is plasticized by an extruding device 101, then a strand 103 is extruded by an extruding die 102, then the strand 103 thus extruded is cooled and solidified by being passed through a cooling water bath 104, then the strand thus solidified is introduced into a strand cutting apparatus 105 through a guide roller 108 and sequentially cut into pellets.
The strand cutting apparatus 105 includes a take-up roller 106 formed by a pair of upper and lower rollers for taking up and sending a strand 103 on a fixed blade 112, the fixed blade 112 having a blade edge extending perpendicularly with respect to the traveling direction of the strand 103, a disc-shaped rotation cutter 110 for sequentially cutting the strand 103 thus sent on the fixed blade 112, and a motor 109 for rotating the rotation shaft 111 of the rotation cutter 110, or the like.
As shown in FIGS. 14 and 15, the rotation shaft 111 of the rotation cutter 110 is pivotally supported in a state that the shaft is disposed so as to be perpendicular to the blade edge of the fixed blade 112 and deviated toward the one side of the fixed blade 112. The rotation cutter 110 is provided on the front surface thereof opposing to the blade edge of the fixed blade 112 with a plurality of plate-shaped blades 113 disposed radially. The blade edge of the plate-shaped blade 113 crosses with the blade edge of the fixed blade 112 with an angle.theta. so as to sequentially cut the strand 103 into pellets P0. The rotation cutter 110 is provided on the front surface thereof with a plurality of guide grooves 114 for guiding the pellets P0 thus cut.
The plurality of plate-shaped blades 113 are fitted into plate-shaped guide grooves 117 provided on the front surface of the rotation cutter 110, respectively. The plate-shaped blades 113 are arranged to be fixed to the rotation cutter 110 by fastening the fastening bolts 116 after adjusting amounts of protrusion of the bladed edges of the plate-shaped blades by rotating forwardly and reversely the push pull bolts 115 which are engaged with the screw holes provided at the rear surface side of the rotation cutter 110, respectively.
According to the aforesaid conventional technique, at the time of adjusting the amounts of protrusion of the bladed edges of the respective plate-shaped blades from the front surface of the rotation cutter so as to provide a predetermined clearance between the bladed edges of the respective plate-shaped blades of the rotation cutter and the blade edge of the fixed blade, the length (distance) of the clearance between the bladed edge of the plate-shaped blades of the rotation cutter and the blade edge of the fixed blade is measured manually by using a clearance gauge at every blade edge of the respective plate-shaped blades. Thus, there arises a problem that the adjusting procedure of the length is troublesome and requires high skill and further there arises a problem as to safety that a hand or a finger may be injured.
Further, since the rotation shaft etc. of the rotation cutter extends due to the thermal expansion, unless the length of the clearance between the bladed edge of the plate-shaped blades disposed at the rotation cutter and the blade edge of the fixed blade is set to be longer than the extension length caused by the thermal expansion, there arises a problem that such an accident occurs that the bladed edges of the respective plate-shaped blades of the rotation cutter interfere with the blade edge of the fixed blade to break the blade edges.